Field of the Invention
The invention relates to a riveting tool for setting blind rivet nuts and/or blind rivet screws, comprising a drive piston which is able to be hydraulically adjusted from an initial position toward an end position; and a pull rod which is releasably and operatively connected to the drive piston and which is able to be adjusted by the drive piston from a rivet receiving position into a setting position; and a coupling element fixing the pull rod and a drawing mandrel to one another in the longitudinal axial direction.
Description of Related Art
Blind rivet nuts and/or blind rivet screws are rivets which have a thread and which, for example, are used when a lower face, an inner face or a rear face of a component is not accessible or only accessible with difficulty. Blind rivet nuts or blind rivet screws also then provide the opportunity of applying threads to components if said components have a wall thickness which is too small in order to permit the cutting of threads.
Riveting tools of the type mentioned in the introduction are used in this case in order to fasten the blind rivet nuts or the blind rivet screws in a convenient manner to the respective component. In this case, the rivet to be set is arranged on the component by a defined deformation, by means of the pull rod which is adjustable between the rivet receiving position and the setting position and which is connected to the drawing mandrel, wherein the drawing mandrel has an internal or external thread which is adapted to the respective rivet to be set. The deformation of the rivet in this case is determined by the stroke of the pull rod applied by the drawing mandrel, from the initial position into the adjustable setting position. For setting the blind rivet nuts and/or the blind rivet screws, said blind rivet nuts and/or blind rivet screws are previously screwed onto the drawing mandrel and introduced into a previously produced opening of the component for receiving the rivet and subsequently set by the stroke of the drawing mandrel applied by the riveting tool, wherein the rivet in this case is deformed in a defined manner as it is supported on a setting head on the riveting tool.
In this case, the length of the setting movement which is determined by the adjustment path of the drawing mandrel connected to the pull rod is essential for the quality of the connection between the set rivet and the component, wherein the pull rod is adjusted by the drive piston. The adjustment path, i.e. the stroke path of the drawing mandrel starting from the rivet receiving position of the pull rod as far as the setting position thereof, determines the strength of the connection of the component and rivet. The adjustment path in this case is dependent, amongst other things, on the material thickness of the components and the rivet used. Generally, in conventional riveting tools the adjustment path is controlled in this case via the hydraulic pressure or respectively the setting force. The setting movement is terminated, for example, by an automated or manual switching-off of a pump unit, when a preset pressure or respectively force is reached.
Such a pressure-controlled or respectively force-controlled setting of rivets, however, has the drawback that it leads to setting processes which are of variable quality, in particular in the case of a manual interruption to the setting process by the operator when a preset pressure is reached. Proceeding therefrom, the object of the invention is to provide a riveting tool of the type mentioned in the introduction by which uniform setting processes of rivets may be carried out with a high degree of repeated accuracy.